This invention relates to reciprocating knife cutters of the type wherein the knife includes a lower cutting portion having at least one sharp cutting edge and is driven by an eccentric mechanism through an upper laterally flexible drive portion or member connected at its lower end to the cutting portion of the knife and at its upper end to the eccentric mechanism so that the lateral component of movement of the eccentric axis is accommodated by lateral flexing of such upper portion, thereby eliminating otherwise needed pivot joints between the eccentric axis and the cutting portion, and deals more particularly with an improvement in such a cutter increasing the ability of the flexible drive portion to withstand the forces imposed thereon during a cutting process and otherwise enhancing the cutter's performance.
A reciprocating knife cutter of the type to which the invention generally pertains is shown, for example, in U.S. U.S. Pat. No. 4,033,214 and in U.S. patent application Ser. No. 06/861,148, filed May 8, 1986, by the same inventor as this application and entitled "CUTTER HEAD AND KNIFE FOR CUTTING SHEE MATERIAL". Another such cutter is shown in U.S. Pat. No. 3,513,444. Such a cutter includes a reciprocating knife, either made as an assembly of parts, as in U.S. Pat. No. 3,513,444 and in U.S. Pat. No. 4,033,214, or made as a one-piece member, as in patent the aforesaid cutting portion and drive portion are integrally joined and made of one piece of material, is the presently preferred embodiment and is shown and described herein by way of example. However, the invention, at least in its broader aspects, also extends to situations where the cutting portion and flexible drive portion are initially separate parts subsequently connected to one another for use in the cutter.
The cutters of the aforesaid patents and patent application are described as being used for cutting cloth or similar sheet material. In the drawings and description which follows the cutter of this invention is likewise described as one usable for cutting cloth, but the invention is also not limited to such application and may instead find use in cutters for cutting various other materials.
A general object of the invention is to provide a cutter of the aforegoing character wherein, in comparison to known cutters of the same general type, the ability of a given flexible knife driving portion to withstand the forces imposed on it during operation is increased to yield a longer service life or, alternatively, the flexible knife driving portion may be made smaller and/or of less mass than previously while nevertheless retaining a service life generally equal to that of previous driving portions.